Blast furnace and method of operating same



May 2, 1933. L. B. WEIDLEIN BLAST FURNACE AND METHOD OF OPERATING SAIE 2Sheets-Sheet 1 Filed Feb. 3, 1932 Qwuentoz A (07/5? 5 7145/01. E/IV- y2, 1933- 'L. B. WEIDLEIN 1,906,680

BLAST FURNACE AND METHOD OF OPERATING SAIE Filed Feb. 5, 1932 2Sheets-Sheet I 2 Patented May 2, 1933 UNITED STATES PATENT OFFICE LUTHERB. WEIDLEIN, OF CLEVELAND HEIGHTS, OHIO Application filed February 3,1932. Serial No. 590,676.

This invention relates to blast furnaces and more particularly to animproved apparatus for disposing of the gas which rises through thestock and is discharged from the top of the furnace.

Prior to the present invention it has been customary in blast furnaceconstruction to provide from one to four outlets for gases at or nearthe top of the furnace. Pipes, commonly known as downcomers, extend fromthese outlets to the dust catcher in which a large amount of the dustcarried from the furnace with the gas is separated out. Thesedowncomers, in the present types of furnaces with which I am familiar,are sometimes extended to the dust catcher individually, sometimes inpairs and at times are all brought together into a common main ordowncomer which then leads to the dust catcher. The length of the pathof the gas from each of the furnace outlets to the dust catcher isdifferent as is the contour of the paths. This results in an unequalresistance to the flow of gas through each of the sepa- 5 rate pipesleading to the dust catcher and frequently causes difficulty with thefurnace operation due to the faet'that the gas passes upwardly throu 'hthe furnace with different velocities in difiierent parts of the crosssection of the furnace. The portions of the fur-- nace below the outletsto the passages having the lesser resistance will conduct more thantheir share of the gas. This not only causes uneven furnace operationbut also re sults in the comparatively rapid wearing away of the wallsof the passages carrying the greatest quantity of gas.

The pipes having greater length, larger number of bends, etc. produce agreater resistance to flow of gas and thereby allows less gas to flow.This lowers the velocity of the gas in the pipes and contributes to therapid building up of dust, coke and other solids in the pipe. Thewithdrawing of unequal quantities of gas from different points on thecross section of the furnace top brings about a number of operatingfaults and disadvantages, among which may be mentioned une ualdistribution of gas through the stoci, causing channeling and resultingin unequal reduction of ores and unequal condition of heat and wear onthe furnace linmg.

It is among the objects of my invention to overcome the difiicultiesnoted above and provide apparatus for carrying away the gas from the topof a blast furnace in which the volume and velocity of gas passing outof each outlet will be equal. Other objects of my invention are: theprovision of means for reducing the resistance to flow of the gas fromthe top of the blast furnace; the provision of an arrangement of pipesfor conducting away the gas from the top of a blast furnace which willpermit of a considerable length of straight vertical pipe above the dustcatcher; the provision of apparatus for carrying awaythe gas from thetop of a blast furnace in which the wear on the pipes will be equalized,the tendency of the ipes to clog minimized and the flow 0 the ascendinggases in the furnace equally distributed over the cross section of thefurnace.

The above and other objects of my invention will appear from thefollowing description of a preferred form thereof, reference being hadto the accompanying drawings, in which- Fig. 1 is a side elevation of ablast furnace and dust catcher incorporating my improved gas conductingmeans between the furnace top and the dust catcher.

Fig. 2 is a fragmentary view of the top of the furnace shown in Fig. 1taken at to the view of Fig. 1.

Fig. 3 is a plan view of the apparatus shown in Fig. 2.

Fig. 4 is a view of the apparatus of Figs. 2 and 3 taken on line 4-4 ofFig. 3. 90

I have found that equal pressure and velocities of the gas in each ofthe several outlet pipes can most advantageously be obtained by havingall of the outlets and uptakes alike, by leading all of the uptakes to acommon junction, preferably on the upwardly extended vertical centerline of the furnace, and conducting the gas from the common junction bya single downcomer to the dust catcher.

Referring to Fig. 1, the blast furnace F is more or lessdiagrammatically represented. Its top is provided with four outletopenings, 1, 2, 3 and 4 (best seen in Fig. 3). Upwardly extending pipesor uptakes 5 extend upwardly from each of the outlets 1, 2, 3 and 4. Theuptakes 5 from the outlets 1 and 4 join at 6 and extend further upwardas a single pipe 7. In like manner the pipes 5 which extend from outlets2 and 3 join at 8 and extend on upwardly as a single pipe 9. The pipes 8and 9 are joined at 10 by suitable pipes 11 and 12 and the downcomer 13extends from this junction point 10 to the dust catcher 14 which may beof any desired and suitable type.

As seen in Fig. l the above arrangement of pipes from the outlets 1, 2,3 and 4'permits of a relatively long, straight, vertically extendingportion 15 of the downcomer 13 directly above the dust catcher 14. Thiscauses the gas to be directed into the dust catcher in a smoothlyflowing stream, free from eddy currents, and increases the efficiency ofthe operation of the dust catcher.

Suitable bleeder valves 16 may be provided at the upper ends of thepipes 7 and 9 above the points where the pipes 11 and 12 lead therefrom.

It will be seen that gases passing from the furnace through each of theoutlets 1, 2, 3 and 4, travel through paths identical in length andcontour until they reach the common junction point 10 from which theyare conducted by the single downcomer 13. This construction gives anequal distribution of gas pressure, volume and velocity in each uptake,reducing the tendency to clog and providing an equalized distribution ofthe ascending gases in the furnace. By taking all the uptakes to acommon junction point 10 and using a single downcomer from this point tothe dust catcher lower back pressure results with equal gas velocitythan can be attained by the use of two or more downcomers because thesingle, relatively large downcomer pipe 13, offers less resistance thantwo or more pipes having a total area equal to that of the single largepipe.

By elevating the point at which the downcomer starts to a point abovethe top structure of the furnace a steeper slope of the downcomer pipeis attainable. This obviates the liklihood of clogging of the downcomerpipe and provides a considerable length of straight vertical pipe abovethe dust catcher which is advantageous for reasons above noted.

Although I have described the illustrated embodiment of my invention inconsiderable detail, it will be understood by those skilled in the artthat modifications and variations thereof may be made without departingfrom the spirit of my invention. For example, any desired number ofoutlets may be provided in the furnace top and the uptakes so arran edas to give paths of equal resistance w ich may be accomplished by makingthe pipes of equal length and contour from each outlet to the commonjunction point. I do not, therefore, limit myself to the exact formshown and described herein but claim as my invention all embodimentsthereof coming within the scope of the appended claims.

I claim:

1. In a blast furnace having a plurality of gas outlets at its top,uptake pipes leadin from said outlets to a common junction point on theupwardly extended vertical center line of the furnace, each of saiduptakes being adapted to offer substantiall equal resistance to the flowof gas theret rough, and a downcomer pipe extended downwardly from saidjunction point.

2. In a blast furnace having a plurality of gas outlets at its top,pipes extending upwardly from each of said outlets, adjacent pairs ofpipes being joined into single pipes and the pairs of single pipes beingjoined at a common junction point on the upwardly extended verticalcenter line of the furnace, whereby substantially equal resistance isoffered to the flow of as from each outlet to said common junctionpoint.

3. In a blast furnace having a plurality of outlet openings at its top,means for conducting gas from each of said outlets to a common unctionpoint lying on the upwardly extended vertical center line of thefurnace, said means comprising pipes forming paths of equal size, lengthand contour from said outlets to said junction point.

4. In combination With a blast furnace having a plurality of gas outletsat its top and a dust catcher, means for conducting gas from saidoutlets to a common junction point lying on the upwardly extendedvertical center line of the furnace, said means comprising pipes ofequal length and contour extending from said outlets to said commonjunction point, and a downcomer pipe extending from said common junctionpoint tosaid dust catcher.

5. In combination with a blast furnace having a plurality of gas outletsat its top and a dust catcher, means for conducting gas from saidoutlets to a common junction point, said means comprising pipes of equalsize, length and contour extending from said outlets to said commonjunction point, and a downcomer pipe extending from said common junctionpoint to said dust catcher.

6. In combination with a blast furnace having a plurality of outletopenings at its top and a dust catcher, conduits extending from each ofsaid outlets to a common junction point disposed on the upwardlyextended vertical center line of the furnace, each of saidconduits beingadapted to offer equal resistance to flow of gas therethrou h, and adowncomer pipe extending from said common junction point to said dustcatcher.

7. In combination with a blast furnace having aplurality of outletopenings at its top and a dust catcher, conduits extending from each ofsaid outlets to a common junction point, each of said conduits havingsub stantially the same internal contour and being adapted to offersubstantially equal resistance to flow of gas therethrough, and adowncomer pipe extending from said common junction point to said dustcatcher.

8. A method of blast furnace operation including the steps of conductingthe blast furnace gases from the furnace to to a point thereabove and onthe upwar ly extended vertical center line of the furnace through pathshaving substantially equal resistance to flow, combining the separatestreams at said point and thence conducting them in a single stream toanother point.

9. In a blast furnace having a plurality of outlet openings at its top,means for conducting gas from each of said outlets to a common junctionpoint lying on the u wardly extending vertical center line of t efurnace, said means comprising pipes forming gas paths of substantiallyequal length from said outlets to said junction point.

10. A method of blast furnace operation which includes the ste s ofconducting the blast furnace gases rom a pluralit of points on thefurnace top to a common unction point thereabove through paths havingsubstantially equal resistance to gas flow, combining the separatestreams of gas at said common junction point and then conducting the gasin a single stream to another point.

11. In a blast furnace having a plurality of outlet openings at its top,means for conducting gas from each of said outlets to a common junctionpoint, said means comprising pipes forming gas paths of substantiallyequal length from said outlets to said junction point.

12. In combination with a blast furnace having a plurality of gasoutlets at its top and a dust catcher, means for conducting gas fromsaid outlets to a common junction point, said means comprising pipesforming gas paths of substantially equal length from said outlets tosaid common junctlon point, and a downcomer pipe extendin from saidcommon junction point to sai dust catcher.

- In testimony whereof I hereunto afiix my signature this 23d day ofJanuary, 1932.

LUTHER B. WEIDLEIN.

